A. Field of the Invention
The present invention relates to distributors for mixing secondary and primary air, and distributing the mixture to the atmosphere at a low noise level.
B. Description of the Prior Art
Modern transit vehicles such as buses and trains require extensive air-conditioning and heating to insure proper comfort levels in these vehicles during the transportation of passengers. Typically, the air-conditioning and heating units are mounted below the transit vehicle. Primary air is circulated through these units and communicated to the interior of the transit vehicle through a system of ducts. This primary fluid is distributed to the interior of the vehicle by fluid distributors typically mounted along the inside and at the bottom of the walls of the transit vehicle. The distributors mix the primary fluid from the heating or cooling unit with secondary fluid within the vehicle and then distribute this mixed fluid to the environment within the transit vehicle resulting in a comfortable temperature level. An example of a prior art unit as described is disclosed in U.S. Pat. No. 3,343,473. Other examples may be found in U.S. Pat. Nos. 3,012,759, 3,194,307, and 3,217,788.
One of the major difficulties encountered in prior art distributors is that as a result of the large volume of mixed primary and secondary fluid that is introduced to maintain the temperature within the vehicle at a comfortable level, as the fluid passes through the distributor, a high frequency noise is created.
Accordingly, it is desirable to provide an air distributor that can efficiently mix secondary and primary air and distribute the mixture to the interior of the vehicle in a large enough volume to maintain the desired temperature level within the vehicle while operating at a minimum noise level. Prior art methods of reducing the noise include the employment of quieting chambers and acoustics. These methods do not significantly reduce noise levels without substantial expense.